Sam used 2 cups of pineapple juice, one serving just needs 2/3 cups of pineapple. 2 divided by 2/3 equals 3 so, Sam made three servings. (in this case 1/2 cup orange juice 3/4 cup Lemon/lime juice 1/3 cup Ginger ale does not matter, you only need to know the pineapple juice.
Yards and meters because they has a good measurement. A mile and kilometer is way to big. A kilometer is 1000 meters and a mile is 5280 feet to be exact.